The present invention relates to a technique of an electrically controlled birefringence(ECB)-in plane switching (IPS) mode liquid crystal display(LCD), and more particularly to the LCD for improving a response speed thereof by treating an alignment film such as the rubbing.
Many study for solving a narrow viewing angle of a twisted Nematic(TN) mode LCD has developed. As one of the researches, a double ECB mode LCD had been produced using a vertical alignment film and a liquid crystal with negative dielectric anisotropy by Fujitsu Co., Ltd in Japan. In the double ECB mode LCD, two domains in which liquid crystal molecules are arranged in a given direction and each domain is symmetrical to each other, thus realizing a wide viewing angle. However, for forming the two domains of the double ECB mode LCD, two-time mask rubbing and optical alignment should be performed, so the manufacturing process for two domains is complicated. In addition, the two-time mask rubbing can result in the destruction of an element underlying the vertical alignment film and further in the difficulty of an application of mass production line for the LCD.
Therefore, the present applicant had been invented a new ECB-IPS mode LCD having a pixel electrode and a counter electrode both formed in a lower substrate and further having a phase compensation film, which was filled in a patent application to Korean Industrial Patent and Trademark Office(KIPO) on May 30, 1997. As shown in FIG. 2A, the liquid crystal molecules over the vertical alignment films formed on the entire surface of the lower substrate on which the pixel electrode and the counter electrode are disposed and the entire surface of a upper substrate, form a given tile angle .theta. with respect to the both substrates when no voltage is applied. The tilt angle .theta. is about 85 to about 90 degree, and each liquid crystal molecule has a different tilt angle .theta. and thus all liquid crystal molecules are randomly arranged at the tilt angle range of about 85 to about 90 degree. Accordingly, a random arrangement of the liquid crystal molecules is made at "on"/"off" of the voltage, and one liquid crystal molecule collide against adjacent liquid crystal molecule after the application of voltage, thus slowing down a response speed of the LCD.